The adoptive transfer of human T lymphocytes that are engineered by gene transfer to express chimeric antigen receptors (chimeric receptors) specific for surface molecules expressed on tumor cells has the potential to effectively treat advanced malignancies. Chimeric receptors are synthetic receptors that include an extracellular ligand binding domain, most commonly a single chain variable fragment of a monoclonal antibody (scFv) linked to intracellular signaling components, most commonly CD3ζ alone or combined with one or more costimulatory domains. Much of the research in the design of chimeric receptors has focused on defining scFvs and other ligand binding elements that target malignant cells without causing serious toxicity to essential normal tissues, and on defining the optimal composition of intracellular signaling modules to activate T cell effector functions. However, it is uncertain whether the variations in chimeric receptor design that mediate superior in vitro function will translate reproducibly into improved in vivo therapeutic activity in clinical applications of chimeric receptor-modified T cells.
There is a need to identify methods for determining elements of chimeric receptor design that are important for therapeutic activity and cell populations to genetically modify and adoptively transfer that provide enhanced survival and efficacy in vivo.